import java.lang.reflect.Array;
import java.util.Arrays;

/**
 * @author ala
 * @date 2024-09-16 15:17
 */
public class Robit {

    public static void main(String[] args) {
        long[] dp = new long[100];
        dp[0] = 1; dp[1] = 2; dp[2] = 4;
        for (int i = 3 ; i < dp.length ; i++) {
            dp[i] = dp[i - 1] + dp[i - 2] + dp[i - 3];
        }
        System.out.println(Arrays.toString(dp));
    }
}
